The present invention relates to a new and improved apparatus for the metering and dispensation of measured volumes of liquid, and has particular utility with respect to the metering and dispensation of oil and similar lubricants.
Industrial machines often require a continuous lubrication of joints and elements during operation. In textile machinery such as knitting machines, for example, the needles and associated elements, such as cams, sinkers and the like, must be continuously lubricated. Lubricant starvation can result in component seizure or breakage, with a resulting down time of the knitting apparatus, and/or the incorporation of defects into the textile product being manufactured.
Knitting machine lubrication is typically performed by use of a lubricant mist generating and delivery system. Such systems deliver an air/lubricant mist, either on a continuous or intermittent basis, to the intended locations in the knitting machine apparatus. Control over the amount of lubricant is important. Too little lubricant can result in system overheating and failure, while over-lubrication is both wasteful of the lubricant and can result in excessive spotting and soiling of the knitted fabric. In addition, the presence of excess lubricant can lead to the entrapment of dust and lint, and can thus also lead to machine damage and/or failure.
Modern oil mist systems are capable of providing a generally constant delivery of lubricant in relatively minute amounts, and can provide transmission to multiple lubrication points for complex systems. Typical lubricators can carry from eight to twenty-two lubrication lines. As they have few moving parts, such systems have extended life spans.
These benefits, however, have an associated cost. Compressed air is the source of energy utilized to break the oil into a mist and to carry the mist to its destination. The compressed air must be clean and dry and the lubricant oils should be of a certain minimum quality. Some high viscosity oils are hard to break into a mist and require an elevated level of air pressure. Further, the output of such lubricant systems is dependent on oil viscosity and the number of lubrication lines, so the system must be carefully configured for the oil used and the number of active lines. The subjecting of the oil to a stream of pressurized air can place a significant strain on oil anti-oxidant additives which are present in the oil along with corrosion inhibitors which are needed to protect the machinery. Most lubricants formulated for textile machinery are water soluble, which requires control over the moisture content of the incoming air. Excessive moisture and pressure differences which may develop in a high pressure system can result in water precipitation, the water mixing with the oil to form soapy complexes inside the lubricator. Extreme care must be observed to prevent such sludge from clogging the oil passages.
It is accordingly a purpose of the present invention to provide an oil delivery apparatus which may be used in conjunction with previously-developed mist-type lubrication nozzles which avoid many of the shortcomings of the prior art. In particular, a lubrication apparatus in accordance with the present invention can generate continuous flows of carefully and precisely metered oil droplets at a relatively low air pressure. Lubricant distribution and spray nozzle operation can be sequenced in an efficient and convenient manner, without the requirement for further complex diverter-type devices. The present invention can operate over a wide range of lubricant densities, including extra heavy lubricants that normally cannot be applied by mist lubrication distribution systems. The construction of the apparatus prevents contact between the oil reservoir and an increased air pressure, minimizing the likelihood of oil oxidation and aeration inside the reservoir. Further, the present system does not require system halt or disassembly to refill the reservoir.
In accordance with the foregoing and other objects and purposes, a fluid metering apparatus for use in conjunction with lubricant distribution systems and fluid dispensation systems in accordance with the present invention utilizes an unpressurized reservoir of a first fluid to be dispensed, such as lubricant, into which a metering. and distribution head is submerged. The head comprises a pair of spaced headers or manifolds through which extend one or more pairs of aligned ports or bores. Each port pair may be associated with a separate distribution line to deliver metered portions of the first fluid to a particular location. Positioned for travel within the space between the two manifolds are metering means having a series of receptacles for the first fluid extending between surfaces of the metering means. The metering means and receptacles may take the form of a plate having a series of precisely-dimensioned apertures extending between surfaces of the plate, the plate being connected to plate drive means. The drive means alternatively exposes a receptacle of the metering means to the first fluid, allowing a precise volume of the fluid to fill the receptacle aperture, and places the aperture into alignment with a port pair in the manifolds. A compressed or pressurized carrier or drive fluid, such as compressed air, supplied to a first port of a port pair, dislodges the entrapped volume of first fluid from its aligned aperture receptacle, and drives the first fluid into the second port of the pair and through the associated distribution line for transmission to the intended target. The drive means subsequently passes the empty receptacle past the port pair, re-exposing the receptacle to the first fluid, whereby the receptacle is refilled. A following passage of the aperture between a pair of ports allows dispensation of the new volume. The process continues on a repeating basis.
In a preferred embodiment of the invention useful for lubricant dispensation the metering means may take the form of a disk having a plurality of receptacle apertures rotating between the two manifolds. Each manifold is provided with a plurality of ports allowing the simultaneous dispensation of lubrication for a plurality of distribution lines and targets.